Regulators



Aug. 6, 1957 J. c. SANDERLIN ET AL 2,802,166

REGULATORS Filed Feb. "20. 1955 Fig.2.

Average A.C. Voltage at Output bf saturating Transformer Average A.C. Supply Voltage Control Ampere Turns mvsmans Jame Q Saderlin United States Patent O REGULATORS James C. Sanderlin, Opelika, Ala., and Louis F. Deise, Baltimore, Md., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application February 20, 1956, Serial No. 566,469

Claims. (Cl. 321--19) This invention relates to regulators and more particuiarly to regulators of the magnetic type.

In certain applications, it is necessary to regulate for not only slow variations in an electrical quantity but also for transient variations in the electrical quantity. A present method of obtaining transient regulation of the required order of magnitude is to use a vacuum tube regulator. The greatest disadvantage of a vacuum tube regulator is in the vacuum tubes which are short-lived, fragile, and generally not dependable. For slow varia- .tions in the line voltage, line frequency and in the load, good regulation maybe obtained by replacing the vacuum tubes with magnetic amplifiers. However, owing to the relatively long response time of magnetic amplifiers, good regulation is not normally obtained for transient variations in the electrical quantity.

An object of this invention is to provide an improved voltage regulator of the magnetic type.

A more specific object of this invention is to provide for maintaining a substantially constant output voltage from a magnetic type voltage regulator irrespective of changes in the load, slow variations in the magnitude and frequency of the input voltage to the regulator and irrespective of sudden or transient variations in the magnitude of the input voltage to the regulator.

Other objects of this invention will become apparent when taken in conjunction with the accompanying drawing, in which:

Figure l is a schematic diagram of apparatus and circuits illustrating this invention;

Fig. 2 is a graph illustrating the transfer curve of the saturating transformer shown in Fig. 1; and

Fig. 3 is a graph illustrating the transfer curve of the magnetic amplifier shown in Fig. 1.

' Referring to Fig. 1, there is illustrated a magnetic type voltage regulator embodying the teachings of this invention. In general, the regulator 10 comprises a saturating transformer or shunt regulator 12, a direct-current load circuit 14, and a series regulator 16 which includes a full-wave doubler-type magnetic amplifier 18. In operation, the shunt regulator 12 and the series regulator 16 cooperate to maintain an electrical quantity, namely the voltage across the direct-current load circuit 14, substantially constant for changes in the load 20, for slow variations in the magnitude and frequency of an alterhating-current source of supply 22, and for transient variations in the magnitude of the voltage of the supply 22.

The saturating transformer 12 comprises a magnetic core member 24, preferably constructed of rectangular loop core material, a primary Winding 26 disposed in inductive relationship with the magnetic core member 24, and a secondary winding 28 disposed in inductive relationship with the magnetic core member 24. In operation, the primary winding 26 is responsive to the alternating-current source of supply 22. In particular, the primary winding 26 is connected in series circuit relationship with a current-limiting impedance member, spe- 2 cifically a current-limiting reactor 30, which functions to limit the magnitude of the current flow through the primary winding 26 when the magnetic core member 24 is substantially completely saturated and the primary winding 26 is not supporting voltage. Thus, under such conditions damage to the primary winding 26 is prevented.

The series circuit including the primary winding 26 of the saturating transformer 12 and the current-limiting reactor 30 is connected to input terminals 32 and 32', the supply 22 likewise being connected to the input terminals 32 and 32'. In operation, the magnitude of the voltage of the supply 22 is always such as to effect a substantially complete magnetic saturation of the magnetic core member 24. Therefore, the average alternating-current output voltage appearing across the secondary winding 28 remains substantially constant even though the magnitude of the voltage applied to the input terminals 32 and 32 does vary. The manner in which the average alternatingcurrent voltage across the secondary winding 28 of the saturating transformer 12 varies with changes in the magnitude of the average alternating-current supply voltage as effected by the supply 22 is repreesnted in Fig. 2 by a transfer curve 34.

The reason the average voltage across the secondary winding 28 of saturating transformer 12 remains substantially constant for changes in the magnitude of the input voltage applied to the input terminals 32 and 32' can be .better understood .by considering that it takes a predetermined number of volt seconds to saturate the magnetic core member 24, and if the input voltage increases, the magnetic core member 24 will saturate within a predetermined time interval which will be of shorter duration than in the case when the input voltage is of lesser magnitude. Further, the area under the voltagetime curves for the primary Winding 26 are of substantially equal magnitude irrespective of the magnitude of the voltage across the input terminals 32 and 32, since the same predetermined volt seconds are required to saturate the magnetic core member 24 each time. Therefore, since there is always a substantially complete magnetic saturation of the magnetic core member 24 for all magnitude-s of voltage across the input terminals 32 and 32, the impedance of the secondary Winding 28 and thus the voltage thereacross remains substantially constant for varying magnitudes of voltage across the input terminals 32 and 32'.

Even though the output voltage across the secondary winding 28 is substantially constant irrespective of the magnitude of the voltage across the input terminals 32 and 32', still the magnitude of the voltage across the secondary winding 28 does vary with changes in the frequency of the voltage across the input terminals 32 and 32'. However, as will be explained hereinafter, the series regulator 16 regulates for this change in voltage which is due to frequency change.

In general, the series regulator 16 includes the magnetic amplifier 18 and circuit means responsive to a measure of the voltage across the direct-current load circuit 14 for controlling the operation of the magnetic amplifier 18. In particular, the magnetic amplifier 18 includes magnetic core members 36 and 38 which have disposed in inductive relationship therewith load windings 40 and 42, respectively. In order to produce self-saturation for the magnetic amplifier 18, self-saturating rectifiers 44 and 46 are connected in series circuit relationship with the load windings 40 and 42, respectively. As illustrated, the series circuit including the load winding 40 and the self-saturating rectifier 44 is connected in parallel circuit relationships with the series circuit including the load winding 42 and the self-saturating rectifier 46, to thus produce a doubler type magnetic amplifier.

Energization for the load windings 40 and 42 is received 3 from the secondary winding 28 of the saturating transformer 12. In particular, the lower end of the secondary winding 28, as shown, is connected to the junction point of the load windings 40 and 42, and thus to one end of the parallel circuit. On the other hand, the upper end of the secondary winding 28, as shown, is connected to the junction point of the self-saturating rectifiers 44 and 46, and thus to the other end of the parallel circuit, through the primary winding 48 of a potential transformer 50 having a secondary winding 52. The function of the potential transformer 50 is to provide a proper impedance match between the magnetic amplifier 18 and the load 20.

Reference windings 54 and 56 are also disposed in inductive relationship with the magnetic core members 36 and 38, respectively. The reference windings'54 and 56 are so disposed on their respective magnetic core members 36 and 38 that current flow therethrough effects magnetomotive forces that oppose the magnetomotive forces produced by the current flow through associated load windings 40 and 42, respectively.

Also disposed in inductive relationship with the magnetic core members 36 and 38 are control windings 58 and 68, respectively. The control windings 58 and 60 are so disposed on their respective magnetic core members 36 and 38 that current flow therethrough produces magnetomotive forces that oppose the magnetomotive forces produced by the current flow through the associated reference windings 54 and 56, respectively.

Referring to Fig. 3, there is shown a transfer curve 62 for the magnetic amplifier 18 which illustrates the manner in which the average alternating voltage across the primary winding 48 of the potential transformer 50 varies with changes in the magnitude of the net control ampereturns as produced by the current flow through the reference windings 54 and 56 and the control windings 58 and 68. in Fig. 3, a vector 64 represents the control ampereturns produced by the current flow through the control windings 58 and 6% when the voltage across the directcurrent load circuit is at the regulated value. The magnitude of the vector 64 varies in accordance with the magnitude of the voltage across the direct-current load circuit 14 and thus in accordance with the magnitude of the voltage across the load 20. On the other hand, a vector as represents the control ampere-turns produced by the current flow through the reference windings 54 and 56. Since the current flow through the reference windings 54 and 56 remains substantially constant during the operation of the regulator 18, the magnitude of the vector 66 remains substantially unchanged.

In order to produce a direct-current voltage across the direct-current load circuit 14, and across the load 20, a full-wave dry-type rectifier 68 having input terminals 70 and 78' and output terminals "72 and '72 is provided. As illustrated, the input terminals 78 and 78' are connected to the secondary winding 52 of the potential transformer 58. A filtcr, including a linear filter reactor 74 and a capacitor 76, is interconnected between the load 20 and the output terminals 72 and 72' of the rectifier 68 in order to produce a smooth direct-current voltage across the load 29.

The circuit means responsive to a measure of the voltage across the direct-current load circuit 14 comprises a parallel circuit one branch of which includes the reference windings 54 and 56 and an impedance member, specificaliy a resistor 78, and the other branch of which includes the control windings 58 and 68 and a voltageregulator tube 88. In practice, the voltage drop across the voltage-regulator tube 86 is much greater than the voltage drop across the control windings 58 and 6 0. Therefore, the voltage-regulator tube 80 functions to maintain the voltage across the other bran-ch of the parallel circuit including the resistor 78 and the reference windings 54 and 56 substantially constant. Thus, the current flow through the reference windings 54 and 56 remains substantially constant during the operation of 4 the regulator 10. In practice, the resistance value for the resistor 78 is so selected as to bias the magnetic amplifier 18 over to a position as illustrated by the vertical ordinate shown in Fig. 3.

The parallel circuit including the reference windings 54 and 56, the resistor 78, the voltage-regulator tube 80, and the control windings 58 and 60 is connected across the direct-current load circuit 14 by conductors 82 and 84 so that the parallel circuit is responsive to the directcurrent voltage across the direct-current load circuit 14.

In series with the conductor 82 is an impedance member, specifically a resistor 86, which functions to limit the magnitude of the current flow through the voltage-regulator tube 80.

The operation of the regulator 10 will now be de scribed. When the direct-current voltage across the load 20 is at the regulated value, then the ampere-turns produced by the current flow through the control windings 58 and 60 just offset the ampere-turns produced by the current flow through the reference windings 54 and 56. This is the condition represented by the vectors 64 and 66 shown in Fig. 3. However, assuming the magnitude of the direct-current voltage across the load 20 increases to a value above the regulated value, due to, for instance, an increase above normal in the frequency of the voltage applied to the input terminals 32 and 32, then the magnitude of the current flow through the control windings 58 and 60 increases. An increase in the current flow through the control windings 58 and 60 decreases the flux level in the magnetic core members 36 and 38 and thus increases the impedance of the load windings and 42. Such an action is represented in Fig. 3 by a vector 88. With an increase in the impedance of the load windings 40 and 42 the voltage across the primary winding 48 of the potential transformer decreases, to thereby decrease the output voltage of the rectifier 68 and thus restore the voltage across the load 20 to the regulated value.

Assuming the direct-current voltage across the load 20 decreases, due to, for instance, a decrease in the frequency of the voltage applied to the input terminals 32 and 32, then themagnitude of the current flow through the control windings '58 and decreases such as represented by a vector in Fig. 3. A decrease in the current flow through the control windings 58 and 60 raises the flux level in the magnetic core members 36 and 38, to thus decrease the impedance of the load windings 40 and 42. With a decrease in the impedance of the load windings 40 and 42 the magnitude of the voltage across the primary winding 48 of the potential transformer 58 increases, to thus restore the voltage across the load 20 to its regulated value.

Although the primary function of the series regulator 16 is to regulate for changes in the magnitude of the voltage across the load 20 due to changes in the magnitude of the frequency of the voltage applied to the input terminals 32 and 32', it is to be understood that the series regulator 16 would also regulate for changes in voltage across the load 20 due to slow variations in the magnitude of the voltage applied to the input terminals 32 and 32'. However, under substantially all conditions the shunt regulator 12 maintains the average alternating voltageacross the secondary winding 28 substantially constant even though the magnitude of the voltage applied to the input terminals does vary and thus the series regulator 16 normally does not need to regulate for changes in the magnitude of the voltage across the load 20 due to changes in the magnitude of the voltage applied to the input terminals 32 and 32. Since the operation of the series regulator 16 would be the same Whether regulating for changes in the frequency or changes in the magnitude of the voltage applied to the input terminals, a further description of such operation is deemed unnecessary.

The apparatus embodying the teachings of this invention has several advantages. For instance, although the regulator 10 comprises substantially all static components,

it maintains a substantially constant output voltage irrespective of changes in the load, slow variations in the magnitude and frequency of the input voltage and irrespective of sudden or transient variations in the magnitude of the input voltage applied to the terminals 32 and 32. Further, since the regulator comprises substantially all static components, maintenance problems are mini- Since certain changes may be made in the above-described apparatus and difierent embodiments of the invention may be made without departing from the spirit and scope thereof, it is intended that all matter contained in the foregoing description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

We claim as our invention:

1. In a regulator system for maintaining an electrical quantity of a load circuit substantially constant when supplied from an alternating-current source of supply, the combination comprising, a saturating transformer having a secondary winding and a primary winding responsive to the alternatingcurrent source of supply, the magnitude of the voltage of the alternating-current source of supply being such as to effect a substantially complete magnetic saturation of the saturating transformer, a magnetic amplifier connected to be energized from the secondary winding of the saturating transformer and connected to control the magnitude of said electrical quantity, and circuit means responsive to a measure of the said electrical quantity for controlling the operation of the magnetic amplifier.

2. In a regulator system for maintaining an electrical quantity of a direct-current load circuit substantially constant when supplied from an alternating-current source of supply, the combination comprising, a saturating transformer having a secondary winding and a primary winding responsive to the alternating-current source of supply, the magnitude of the voltage of the alternating-current source of supply always being such as to effect a substantially complete magnetic saturation of the saturating transformer, a magnetic amplifier having a magnetic core member and a load winding, a reference winding and a control winding disposed in inductive relationship with the magnetic core member, circuit means for interconnecting the load Winding with the secondary winding of the saturating transformer and with the direct-current load circuit so that the load winding can effect a change in the magnitude of the voltage applied to the direct-current load circuit, and other circuit means for rendering said control winding responsive to the voltage across the direct current load circuit and for supplying said reference winding with a substantially constant current.

3. In a regulator system for maintaining an electrical quantity of a direct-current load circuit substantially constant when supplied from an alternating-current source of supply, the combination comprising, a saturating transformer having a magnetic core member constructed of substantially rectangular loop core material, a secondary win-ding, and a primary winding responsive to the alternating-current source of supply, the magnitude of the voltage of the alternating-current source of supply being such as to efiect a substantially complete magnetic saturation of the saturating transformer, a magnetic amplifier connected to be energized from the secondary winding of the saturating transformer and connected to control the magnitude of said electrical quantity, and circuit means 6 responsive to a measure of the said electrical quantity for controlling the operation of the magnetic amplifier.

4. In a regulator system for maintaining an electrical quantity of a direct-current load circuit substantially constant when supplied from an alternating-current source of supply, the combination comprising, a saturating transformer having a secondary winding and a primary winding responsive to the alternating-current source of supply, the magnitude of the voltage of the alternating-current source of supply always being such as to effect a substantially complete magnetic saturation of the saturating transformer, a magnetic amplifier having a magnetic core member and a load winding, a reference winding and a control winding disposed in inductive relationship with the magnetic core member, circuit means for interconnecting the load winding with the secondary winding of the saturating transformer and with the direct-current load circuit so that the load winding can effect a change in the magnitude of the voltage applied to the direct-current load circuit, a parallel circuit, one branch of the parallel circuit including a voltage-regulator tube and said control winding and the other branch of the parallel circuit including a resistor and said reference winding, and other circuit means for connecting the parallel circuit to the direct-current load circuit so that the parallel circuit is responsive to a measure of said electrical quantity.

5. In a regulator system for maintaining the directcurrent output voltage of a load circuit substantially constant when supplied from an alternating-current source of supply, the combination comprising, a saturating transformer having a primary winding and a secondary winding, a current-limiting impedance member connected in series circuit relationship with the primary winding, the series crcut beng connected to be responsive to the alternatingcurrent source of supply the magnitude of whose voltage is such as to efiect a substantially complete magnetic saturation of the saturating transformer, a magnetic amplifier having a magnetic core member and a load winding, a reference winding and a control winding disposed in inductive relationship with the magnetic core member, said reference winding and said control winding being so disposed as to effect opposing magnetomotive forces, circuit means for interconnecting the load winding with the secondary winding of the saturating transformer and with the direct-current load circuit so that the load winding can effect a change in the magnitude of the voltage applied to the direct-current load circuit, a parallel circuit, one branch of the parallel circuit including a voltageregulator tube and said control winding and the other branch of the parallel circuit including a resistor and said reference winding, and other circuit means for connecting the parallel circuit to the direct-current load circuit so that the parallel circuit is responsive to a measure of said electrical quantity.

References Cited in the file of this patent UNITED STATES PATENTS 2,442,960 Pohm June 8, 1948 2,723,372 Eagan et al. Nov. 8, 1955 2,725,515 Horton Nov. 29, 1955 2,739,282 Evans Mar. 20, 1956 2,763,827 Evans Sept. 18, 1956 2,764,725 Buie Sept. 25, 1956 2,777,047 Stevens Ian. 8, 1957 

